Sweet pickles sound delicious.  Also it gives her an idea… several spells can achieve effects analogous to, or directly equivalent to, aging things!  It seems a rapid food aging spell ought to be theoretically possible!  She hopes the closest analog isn’t transmutation.

A library search later and… Sands of Time is necromancy, which is good, but 3rd circle, so well beyond her magical strength and out of reach of her finances (at least without months of more careful saving than she likes doing) to even get a scroll of to study.

(Regarding the Common Pickle) While such Mundane Concerns may seem Beneath the purview of One such as Lady Eriape, who has long transcended the Need for Mortal Sustenance, We find Ourselves Compelled to address this matter. We have found that the Containment of nearly Every Humor or Substance in Glass over the course of Years may lead to Grevious Mishap, as continous Gaseous Emanations extrude, and Transform these Glass Receptacles into VERITABLE PETARDS. The Devastation wrought by such has rendered many a Priceless Tome of Arcane Lore to Sodden Pulp. Fortunately, there is a Spell, of the Obverse Power, which Infallibly prevents this, which is reproduced Below, for the benefit of the Common Laundry Wizard of Cheliax. 

That's awesome!  She'll need to actually turn the instructions into a transcribed spell in her spellbook (since Eriape apparently doesn't have thousands of gold pieces in ink to make hundreds of spellbook quality copies for her pamphlet), which means a few days effort minimum, assuming it isn't a cruel joke, and paying to have Thea on standby in case the spell is innately lethal to living casters or explosively flawed in stabilization.  And then to actually use it, she'll need some at least a few mice to test the result on, which means convincing Thea to let her keep mice, which means a bit more cost.  But still, new spell!

Her preliminary research shows it is a variant of the not too uncommon preserve but there is some trick to getting it to last longer...

Detect poison operates relative to the caster.  She doesn't even need to use lab mice, food preserved by Eriape's Preserve blatantly shows up as clearly poisonous.  She will still want the lab mice, maybe in conjunction with very good labeling and a Divine Caster with Purify Food and Drink it still has usefulness.

Interestingly... purify food and drink also removes its preservative effect, so the food would have to be stored poisonous, then purified to eat.

...Pickling is probably a safer option anyway, but it is still an advancement to magic as a whole.

A DIRE WARNING ON A RECENTLY REVEALED SPELL

The variant of the 1st circle spell PRESERVE, spread in Lady Eriape's Badger Pamphlets, renders the food poisonous to living creatures!  It is detectable as poison to a laundry wizard's DETECT POISON.  DO NOT EAT FOOD PERSERVED THIS WAY!  Research is ongoing into if purify food and drink renders it safe, but this is NOT CERTAIN!

FURTHER RESEARCH AND WARNING ON THE PRESERVATION SPELL OF THE BADGER (LADY ERIAPE)

This is a reminder that ERIAPE'S PERSERVE, the variant of PERSERVE described in a BADGER PAMPHLET renders food preserved by it POISONOUS to living creatures.  A PURIFY FOOD AND DRINK cast by a cleric can render food preserved this way apparently safe to eat, but also ENDS the preservation effect.  Thus, the PURIFY FOOD AND DRINK must only be used after one no longer wishes to preserve the food.  MAKE SURE TO CLEARLY LABEL FOOD PRESERVED by this spell, so that no ACCIDENTAL POISONING OCCURS through failure to PURIFY FOOD AND DRINK.  THE LONG TERM EFFECTS BEYOND IMMEDIATE POISON are still UNCERTAIN, even with a PURIFY FOOD AND DRINK.  USE ONLY AT YOUR OWN RISK!

FURTHERMORE an additional issue exists: the taste of food PRESERVED by this spell is usually HOLEY AWFUL.  PRESTIDIGITATION is mostly insufficient to fix this taste (and is obviously completely unable to counteract POISON).  In already pungent foods, such as (unsweetened) PICKLES, the taste is manageable, and indeed has CULINARY POTENTIAL, but the usage as a preservative is questionable as PICKLES are already preserved by the VINEGAR and nonmagical SKILL of the PICKLER.

On preserving fruit and the argument against sweet pickles.
Honey is such an overpowering flavour! Sweet pickles end up so samey. Why even bother storing fruit in honey when you will barely taste the fruit at the end under all that honey taste! What one might do to preserve fruit without the ever overpowering flavour of honey is to COOK THEM INTO JAM! So in a way you are putting fruit in sugar water to preserve it, you just also cook it down. In this way you can preserve the flavour of fruits for when they are out of season.

Summoned Goodberries also jam quite well!
Consider jams as marinades for your next Owlbear roast.